In a nonaqueous electrolyte battery using a carbon-based active material in a negative electrode, there is a problem that degradation of the negative electrode is accelerated at each of the ends of charge and discharge. Thus, in the nonaqueous electrolyte battery using the carbon-based active material in the negative electrode, there is adopted a design in which the capacity of the negative electrode is excessively increased with respect to the capacity of a positive electrode. According to such a design, a use range of the negative electrode is limited, and the degradation of the negative electrode can be prevented.
However, in a battery designed such that the capacity of one of the positive and negative electrodes is excessively increased with respect to the capacity of the other electrode, a surplus capacity is generated, and therefore, it is disadvantage in terms of energy density.
On the other hand, in a nonaqueous electrolyte battery including a negative electrode including a lithium titanate, degradation of the negative electrode at each of the ends of charge and discharge is extremely small. Thus, in the nonaqueous electrolyte battery including the negative electrode including the lithium titanate, it is not necessary to adopt such a design that the capacity of the negative electrode is made excessive in order to prevent the degradation of the negative electrode.